Silver halide emulsion containing yellow benzothiazole azo dyes useful in the silver dye bleaching process

ABSTRACT

SILVER HALIDE EMULSION CONTAINING YELLOW BENZOTHIAZOLE AZO DYES TO BE USED IN THE SILVER DYE BLEACH PROCESS.

United States Patent 01 3,585,039 Patented June 15, 1971 hoe SILVER HALIDE EMIILSION CONTAINING YEL- Low BENZOTHIAZOLE AZO DYES USEFUL IN THE SILVER DYE BLEACHING PROCESS for prolonged periods. High fastness to light as well as resistance to acid gases such as occur, for example in the atmosphere of industrial areas, are also particularly important. For thes reasons, the dyes previously de- Kaflheinz Kabitzke, Cologne Buchheim, Erich Bockly, 5 lscri lzeg forf the sllver dye bleachlng process are only of Leverkusen, Steinbuchel, Justus Danhauser, Cologneuse P stammheim KarhHeinz Freytag, Leverkusen, and Hans It 1s the ob ect of the invention to find yellow azo dyes Vetter, Cologne-Stammheim, Germany, assignors t for use in the s1lver dye bleaching process which are easy Agfa-Gevaert Aktiengesellschaft, Leverkusen, Germany to prepare, are compatible with the photographic layers, No Drawing. Filed Mar. 4, 1969, Ser. No. 804,255 e.g. are readily soluble, and have little influence on the Claims P y, application Germany, 1968, viscosity of the casting solution, and have spectral proper- P 16 22 923-5 ties which meet the requirements of the photographic Int. Cl. G03c 1/10 process. 96-99 6 Clam It has now been found that light-sensitive photographic materials which comprise at least one silver halide emul- ABSTRACT OF THE DISCLOSURE sion layer are eminently suitable for use in the silver dye bleaching process 1f they contam m the said emulsion lay- S lver hallde emulsion contammg yellow benzothlazole er an azo dye of the following formula Which contains at azo dyes to be used in the silver dye bleach process. least one lf i acid group:

S R: This invention relates to color photographic materials R1 for use in the silver dye bleaching process which contain N=NR4NH X exceptionally light-fast yellow azo dyes. The production of color photographic images by the 25 R2 N silver dye bleaching process is known. In this process, the n dye which is present in those areas of a homogeneously in which colored colloidal layer where a silver image has previ- R1 is hydrogen or alkyl f bl containing up to 3 Y Produced Photograhhlcally 1S bleached carbon atoms, e.g. methyl; benzothiazolyl, in particular Wise a Strongly acld hleaehlhg hath- The dye used 15 alkyl-substituted benzothiazolyl, e.g. methylbenzothiazolyl; usually an azo dye. If direct positive images or duplicate R2 and R3 are hydrogen or sulfo; positives are to be produced from diapositives, simple R4 i a arylene group, in particular phenylene or black-and-white development is used to produce the silver naphthylene which group may be substituted by one or image Which is then negative P the Onginal- T image more substituents, e.g. by saturated or olefinically unsaty homogeneously dletl'lhuted 111 the y 111 the case urated aliphatic groups, preferably containing up to 5 carof a multicolor material in the three layers, is destroyed bon atoms, methyl, which aliphatic groups may in Where the Y image'has e e as a turn carry substituents, e.g. carboxyl or sulfonic acid result the fe y Image 18 Phtalhed Y e 1s a he groups, other suitable substituents being halogen, e.g. chlotive of the onglnal. If a silver image whlch 1s a pos1t1ve fine or bromine alkoxy having f bl up to 5 of the original is produced, e.g. by black-and-whlte reversal 40 hon atoms, eh. methoxy or ethoxy, amino or Substituted development or by the bromine ion dilfusion process or amino alkyl amino or acyl amino, especially Su1fo the silver salt diffusion process, a dye image is obtained behzoylamino; lf and carhoxyl; Which is pp in gradation t0 the Original, in this X is a monovalent or divalent radical which is prefere e a f'e 9 image is P Q after dye bleach ably derived from an aliphatic or aromatic monoor dimg 1f the original 1s a color negatlve. carboxylic acid, a particularly suitable monovalent acyl The y use 111 thls pf e must satlsfy Partleularly radical being benzoyl or substituted benzoyl and a suitstringent requlrements. ThlS is because these dyes must able divalent acyl radical being (1) carbonyl, the he speehauy Sultahle, must be Well hleaehahle, and u radical of a saturated or unsaturated aliphatic dicarboxylic have high fasthessl t ih'i-h g t i, the gly acid preferably containing up to 12 carbon atoms, such as not impair t e qua i ies o e p o ograp ic em sion an they must be completely diifusion-fast in gelatin, which COCH CHCO CO(CH2)3CO or is almost exclusively used as the layer forming substance. CO(CH CO or (3) the radical of an aromatic di- However, the dyes must be readily soluble so that sutficarboxylic acid, especially a benzene dicarboxylic acid ciently concentrated solutions such as are required for such as isophthalic acid, or terephthalic acid; also pyrimodem casting processes may be easily prepared. The dine dicarboxylic acid or furan dicarboxylic acid; behaviour of the dyes in the silver halide emulsion is also It is '1 or 2. very important. Thus, for example, they must not alter The following are examples of dyes which have proved the viscosity of the casting solution even if left to stand to be suitable:

1) Scan $0311 I S I (H) 2) SOzH SOaH I S IQ MUiIQMQQBLHI S0311 SOaH SO3H 3013:

IIIH

o S i ll ll mo T -N=N -o- -NHC-HN son: soul 0 o 0 o=o--som S 0311 s ii mo @N=N-NHC-HNCI N NH 01 CH2)4S 03H OaH The dyes for use according to the invention are prepared by methods usual in azo dye-chemistry.

DYE NO. 8

7-sulfo-6-methyl-2-(4-amino 3-su1fophenyl) benzothiazole is indirectly diazotised and coupled under acid conditions with 3-methylaniline. The isolated coupling product is dissolved in water and phosgenated in the usual manner to produce the final dye.

DYE NO. 17

7-sulfo-6-methyl-2-(4-amino 3-su1fophenyl) benzothiazole is indirectly diazotised and coupled under acid conditions with 3-maleoylamino-aniline. The isolated coupling product is reacted in the usual way with terephthalic acid dichloride to produce the final dye.

One special advantage of these dyes over other known yellow azo dyes is the ease with which they can be prepared, since the aminophenylbenzothiazoles from which they are derived are very easily accessible in practice. They can therefore be prepared in a particularly pure state so that the undesirable effects or impurities are avoided. Their spectral properties as well as the brilliance of the dyes are excellent. They also have excellent compatibility with silver halide gelatin emulsions which makes them very valuable and very uniform distribution in the layer is achieved. It is, in particular, in this last property that many of the known dyes, which would otherwise be useful on account of their spectral properties, are not satisfactory.

Owing to their excellent light-fastness, ability to be bleached and dilfusion fastness, the dyes according to the invention can be used in various ways in color photographic layers for the silver dye bleaching process. As will be shown in the following examples they are used to particular advantage as image dyes in layers which are subjected to a simple black-and-white negative development and accordingly yield direct positive color images in the subsequent dye bleaching bath. They may also be used for a black-and-white reversal development, in which case dye images which are opposite in gradation to the original are obtained after the layers have been processed in the treatment baths of the silver dye bleaching process. Such images are required for the production of positive colored prints or transparencies from color negatives.

The dyes mentioned above are substantially inert to the usual quantities of emulsion additives such as stabilisers, plasticisers, wetting agents, hardness and other substances, e.g. added sensitisers.

As will be shown in the following example, they can be bleached completely to pure white in various bleaching baths, e.g. in those based on quinoline and iodide or on thiourea and different bleaching catalysts such as quinoline, quinoxaline, phenazine derivatives and the like and therefore leave virtually no colored fog.

The dyes for use according to the invention are added in the usual manner to silver halide emulsions which may contain silver chloride, bromide or mixtures thereof, if desired, with silver iodide. Color photographic layers produced with these dyes can be cast on supports made of paper, baryta paper, polyethylene-coated paper, polypropylene-coated paper or on paper which has been rendered hydrophobic in some other way, glass, metallised foils of all types or transparent or pigmented cellulose acetates as well as on transparent or pigmented substrated foils of polyester, etc. Apart from their use as image dyes, for the silver dye bleaching process, the dyes according to the invention are also very suitable for the production of filter layers for photographic purposes on account of their high fastness to light and their spectral properties.

EXAMPLE 1 4.5 g. of the dye of Formula 8 are dissolved in 400 ml. of 4% gelatin solution with 0.7 g. of saponine, and 800 ml. of a melted silver bromide gelatin emulsion are added. After the addition of 20 ml. of a 1% aqueous solution of N,N',N"-tris-acryloylhydrotriazine-(1,3,5) as hardener, the emulsion is cast on a layer support of baryta paper and on another support of cellulose triacetate in a layer thickness which corresponds to a silver application of 0.6 to 0.9 g. of silver per m and the layers are dried. A strip of each material prepared as described above is exposed behind a grey step wedge with yellow or white light and is worked up as follows:

(1) Development: minutes in the following developer:

p-methylaminophenol-1 g. hydroquinone3 g.

sodium sulphite anhydrous13 g. sodium bromide1 g.

soda anhydrous-26 g. water-up to 1000 m1.

(2) Wash: 5 minutes. (3) Fix: 5 minutes in the following bath:

sodium thiosulphate cryst200 g. potassium metabisulphate20 g. water--up to 1000 ml.

(4) Wash: 5 minutes. (5 Harden: 5 minutes in the following bath:

formalin (30% )--100 ml. sodium bicarbonate-2 g. Water-up to 1000 ml.

(6) Wash: 5 minutes. (7) Dye-bleach: minutes in the following bath:

potassium iodide-10 g. sodium hypophosphite10 g. conc. sulphuric acid-75 ml. quinoline-50 ml.

waterup to 1000 ml.

(8) Wash: 5 minutes. (9) Bleach-fix: 10 minutes in the following bath:

tetrasodium-ethylene diaminotetraacetate26 g. soda anhydrous-24 g.

ferric chloride g.

sodium sulphite, anhydrous13 g.

sodium thiosulphate200 g.

waterup to 800 ml.

(10) Wash: 15 minutes.

After drying, pure yellow dye wedges with excellent gradation, high brilliance and good whites are obtained which do not show any signs of dye diffusion and have excellent fastness to light. The layers are very suitable for the production of the yellow part of the image in a multicolor photographic material.

EXAMPLE 2 A multi-layered color photographic material for the silver dye bleaching process is prepared as described below. The following layers are cast sucessively on a support of baryta paper:

(1) A red-sensitized layer which contains, in 500 g. of an iodide-containing (5 mols percent) silver bromide emulsion, 12 mg. of the sensitizer according to Example 11 of German patent specification 1,177,481 and 2.7 g. of the dye of the following formula:

SOaH

the preparation of which is described in French patent specification 1,471,787, dissolved in 200 ml. of a 2% gelatin solution which in addition contains 10 ml. of a 1% aqueous solution of N,N',N"-trisacryloyl-hexahydro- 1,3,5-triazine as hardener and 0.5 g. of saponin. The amount of silver applied is 0.8 g. per m (2) An intermediate layer of 2% gelatin solution.

(3) A green-sensitive layer which contains, per 500 ml. of an iodide-containing (5 mols percent) silver bromide emulsion, 15 g. of the sensitizer according to Example 2 of German patent specification 1,177,481 and 3.5 g. of the dye of the following formula:

HOaS- the preparation of which is described in German patent specification 1,039,840, dissolved in 200 ml. of a 2% gelatin solution which in addition contains 10 ml. of a 1% aqueous solution of N,N',N"-trisacryloyl-hexahydro-l,3,5- triazin as hardener and 0.4 g. of saponin. The silver application is 0.75 g. per m.

(4) An intermediate layer of a 4% gelatin solution containing per litre 8 g. of tartrazine.

(5) A non-sensitized emulsion layer containing silver bromide as described in Example 1.

(6) A protective layer of 2% gelatin solution.

After drying, the layer is exposed behind a multicolored diapositive and worked up as described in Example 1, but the treatment time in the dye bleaching bath is increased to 15 minutes. If the sensitivities of the individual layers are correctly adjusted to each other, a faithful reproduction of the colors of the original is obtained after washing and drying.

23 We claim: 1. A light-sensitive color photographic material containing at least one silver halide emulsion which contains a yellow monoor bisazo dye of the following formula:

in which: R is hydrogen, alkyl or a benzothiazolyl group; R and R are hydrogen or sulfo; R is an arylene group; X is a monovalent or divalent acyl radical; and n is 1 or 2.

2. A light-sensitive color photographic material according to claim 1, wherein R represents methyl and R is sulfo in the 7-position.

5. A light-sensitive color photographic material according to claim 1, wherein X represents a divalent radical of a benzene dicarboxylic acid, of furmaric acid or -CO- and n is 2.

6. A light-sensitive color photographic material according to claim 1, wherein the azo dye has the following formula:

S 0 3H S 0 311 N Ha C References Cited UNITED STATES PATENTS 3,210,190 10/1965 Anderan et al. 9699 3,493,372 2/1970 Gompf et al 96-99 3. A light-sensitive color photographic material ac- I. TRAVIS BROWN, Primary Examiner cording to claim 1, wherein R denotes sulfo in the orthoposition to the azo group.

4. A light-sensitive color photographic material according to claim 1, wherein R represents a phenylene group substituted with alkyl or acylamino.

US. Cl. X.R. 

